I need your technical support regarding the WCF service and Proxy server
authentication. Following the scenario.

The remote server returned an unexpected response: (407) Proxy
Authentication Require

I have hosted WCF services on Windows Longhorn Server Beta 3. The WCF
services is having the endpoint as BasicHttpBinding.
<behaviors>
            <endpointBehaviors>
                <behavior name="NewBehavior"/>
            </endpointBehaviors>
            <serviceBehaviors>
                <behavior name="NewBehavior">
                    <serviceMetadata httpGetEnabled="true"/>
                </behavior>
            </serviceBehaviors>
        </behaviors>

The client is developed in WPF as a smart client application (ClickOnce
Application) which is using this service.
<basicHttpBinding>
                <binding name="BasicHttpBinding_IBedraClubRedeemedManager"
closeTimeout="00:01:00"
                openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
                allowCookies="false" bypassProxyOnLocal="false"
hostNameComparisonMode="StrongWildcard"
                maxBufferSize="5000000" maxBufferPoolSize="524288"
maxReceivedMessageSize="5000000"
                messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
                useDefaultWebProxy="false">
                    <readerQuotas maxDepth="32" maxStringContentLength="8192"
maxArrayLength="16384"
                    maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                    <security mode="None">
                    </security>
                </binding>

Now we are not having any problem till date for the communication with the
service, but to one of our customer centers we are failed to use the service.
When they are trying to start the application they are getting the error
message as mentioned below.

From this error message I just came to know that they are using the ISA
server 2006  as a proxy server and Firewall. And we are failed to
authenticate our request in the proxy server.  I could not authenticate my
request in proxy server. I tried following code segment but none of them
works.

UserManagerClient objUserClient = new UserManagerClient();

1.            
objUserClient.ChannelFactory.Credentials.Windows.ClientCredential.UserName =
"ilink";
objUserClient.ChannelFactory.Credentials.Windows.ClientCredential.Password =
"ilink";

2.
objUserClient.ClientCredentials.UserName.UserName = "ilink";
objUserClient.ClientCredentials.UserName.Password = "ilink";

3.
objUserClient.ChannelFactory.Credentials.UserName.Password = "ilink";
objUserClient.ChannelFactory.Credentials.UserName.UserName = "ilink";

In all the above statement “ilink” is the username and password created in
ISA server.

Also I have mention not to use the default proxy settings.(
objBinding.UseDefaultWebProxy = false;)
None of the above works and I could not find any to validate or pass the
Proxy credentials

Please if you could help me in this scenario I would really appreciate and
can maintain the relationship with our customer. This is now really very
urgent to come to the solution.